Cidex®-OPA is a high level disinfectant commonly used for processing heat sensitive medical devices.

We report 4 patients who experienced 9 episodes of anaphylaxis following cystoscopy after a urology practice switched from using CIDEX® to CIDEX®-OPA for sterilizing their cystoscopes.

Allergic evaluations consisted of: skin testing to saline, histamine, lidocaine, and latex, Ciprofloxacin, Macrodantin, Cidex® and Cidex®-OPA. Total IgE and latex-specific IgE.

The 4 patients were evaluated after (3) had experienced two episodes of anaphylaxis and (1) three episodes following outpatient cystoscopy for ongoing evaluation of bladder cancer. Skin testing of subjects to Lidocaine, latex, Ciprofloxacin and Macrodantin, and specific IgE to latex were negative. Skin testing to Cidex® and Cidex®-OPA were performed on 5 “volunteers” and all tests were negative. Skin testing to Cidex® on the four patients were also negative. However, skin testing to Cidex®-OPA resulted an immediate wheal and flare reaction in all 4 patients within 20 minutes (avg. wheal 24.2 mm.) and late reaction between 6 and 24 hours (avg. induration 56.3 mm.). Subsequent to the testing, one of the patients returned for repeat cystoscopy but Cidex® was not used to sterilize the cystosope. The patient tolerated the procedure without any allergic manifestations.

Cidex®-OPA (ortho-phthaldahyde) solution should be considered as a cause of anaphylactic/allergic reactions following cystoscopy and possibly instrumentation with other medical devices.